#include <unistd.h>

void swab(const void *restrict _src, void *restrict _dest, ssize_t n)
{
    const char *src = _src;
    char *dest = _dest;
    for (; n>1; n-=2) {
        dest[0] = src[1];
        dest[1] = src[0];
        dest += 2;
        src += 2;
    }
}
